Planning for post-disaster accessibility is essential for the provision of
emergency and other services to protect life and property in impacted areas.
Such planning is particularly important in congested historic districts where
narrow streets and at-risk structures are more common and may even prevail.
Indeed, a standard method of measuring accessibility, through the use of
isochrones, may be particularly inappropriate in these congested historic
areas. Bucharest, Romania, is a city with a core of historic buildings and
narrow streets. Furthermore, Bucharest ranks second only to Istanbul among
large European cities in terms of its seismic risk. This paper provides an
accessibility simulation for central Bucharest using mapping and geographic information system
(GIS) technologies. It hypothesizes that all buildings in the risk 1 class would
collapse in an earthquake of a similar magnitude to those of 1940 and 1977.
The authors then simulate accessibility impacts in the historic centre of
Bucharest, such as the isolation of certain areas and blockages of some
street sections. In this simulation, accessibility will be substantially
compromised by anticipated and extensive building collapse. Therefore, policy
makers and planners need to fully understand and incorporate the serious
implications of this compromised accessibility when planning emergency
services and disaster recovery responses.

A longitudinal analysis of natural hazards in major urban areas shows an
increasing awareness of the frequency of disasters and especially of
earthquakes (Eshghi and Larson, 2008; Armaş, 2012; Lu and Xu, 2014).
Indeed, earthquakes are among the natural disasters that generate the
greatest human and material losses (Geis, 2000; Armaş and Avram, 2008;
Atanasiu and Toma, 2012). Their impacts demand a prompt response from
decision makers and the wider population, through the proper management of
emergency situations (Waugh and Streib, 2006). In any disaster situation,
one of the most important factors across all the disaster phases is
public–private emergency cooperation for post-disaster accessibility and
efficient intervention. By developing a model to harmonize this strong
cooperation, Wiens et al. (2018) identify efficient ways to improve the
logistics of these operations during crisis management.

Many areas of high seismic risk are urbanized and densely populated (Pollino
et al., 2012; Vatseva et al., 2013). In addition, and coincidentally, many
countries experiencing economic transitions are characterized by urban
growth that is uncontrolled, and in large and medium-sized urban centres
such growth can be especially chaotic (Salvati, 2014). Thus, an increase in
the human and economic cost of such disasters can be reasonably anticipated.
Furthermore, many new buildings; new structures; and, sometimes, newer pieces
of infrastructure frequently fail to comply with the construction
regulations established for areas of differing seismic vulnerability,
especially when there are strong pressures for rapid development. Finally,
the characteristically long time lags between pairs of strong earthquakes
(Schweier and Markus, 2006) can dull public awareness of the potential
impacts of such disasters and render those in charge of emergency
management complacent.

Earthquakes require a specific disaster planning approach (Armaş, 2008;
Boştenaru Dan and Armaş, 2015). This is because, unlike disasters that can
be anticipated in the short term (such as storms), there is little or no
delay between the occurrence of the earthquake and the subsequent loss of
life and property damage. Therefore, emergency response activities must be
executed very quickly and efficiently (Wegscheider et al., 2013). For cities
with a high earthquake risk, an important factor is public awareness of such
events. This conditions the population towards the importance of quick
response measures, which can help to reduce property damage and, more
importantly, the number of casualties (Armaş and Avram, 2008). However,
no matter how well organized the mitigation process, the disastrous effects
of major earthquakes cannot be totally avoided (Momani and Salmi, 2012).

Post-disaster recovery needs to transfer the most debated academic concepts
(disaster resilience, for example) into appropriate politics and
transform them into real tools for adequate planning. Governments have
an important task: to prepare the population and all stakeholders for future
similar events (Comerio, 2014).

In recent years, seismic risk management has been more fully studied and
developed so as to establish a series of priorities related to the
rehabilitation of those buildings considered to be of major importance,
including schools (Grant et al., 2007; Raffaelle et al., 2013; Panahi et al.,
2013), public institutions, historic buildings, and monuments (Grasso and
Maugeri, 2009; Pessina and Meroni, 2009). Urban earthquake planning therefore
needs to be more proactive (Boştenaru Dan et al., 2014), and there is a
demonstrated requirement for coherent urban policies (Ianos et al., 2017) to
mitigate the inevitable occurrence of blockage points during emergency
interventions.

In emergency situations, the key response element is rapid accessibility to
places where possible casualties may be located. Timely intervention within
the first 2 h is critical in saving the wounded and in identifying the
safest access routes for specific emergency equipment. As Fiedrich (2007)
suggests, the disaster responses made during the first 3 days are
fundamental. After that, the main goals are invariably rescuing trapped
victims and treatment of the injured, though ongoing fire control may also
be required in some cases.

In general, natural hazard management includes the development of impact
scenarios before the actual disasters occur (Bakillah et al., 2013). In this
context, geographic information systems (GIS) techniques may be particularly useful in developing
decision-making and response scenarios for potential earthquake disasters.

Our study shows that special attention should be paid to accessibility in the
historic centres of large cities (Ianos and Cepoiu, 2009). Historic city
centres are characterized by intense pedestrian traffic and by a high
proportion of attraction points (clubs, restaurants, hotels, etc.) which
result in high concentrations of people. Since the core of the historic
centre of Bucharest is characterized by a high number of buildings that were
strongly affected by earthquakes in the last century, we can reasonably
speculate that determining their accessibility in an emergency situation will
facilitate quick intervention in areas where injured people – either direct
casualties or victims of earthquake-related phenomena such as fires, gas
accumulations, or local flooding – are likely to be concentrated. The main
objective of the study is to integrate geospatial data using thematic mapping
products with GIS techniques in order to provide seismic risk management
solutions for Bucharest. We therefore seek to provide concrete data and
comprehensible information that can enable decision makers to implement and
prioritize their disaster management strategies. A similar study, based on
different hazard scenarios and a deep analysis on social vulnerability in
Bucharest, identifies the importance of fire stations, hospitals, and parks
in post-disaster situations (Armaş et al., 2016).

Unlike most studies of community response following an earthquake occurrence
and the critical analysis of the emergency situations management generated
thereby (Pollino et al., 2012; Wegscheider et al., 2013; Lu and Xu, 2014),
the present study demonstrates the importance of GIS analyses in detecting
potential congestion and inaccessibility issues in areas where buildings are
most likely to collapse and accessibility issues are most likely to arise as
a result of an earthquake.

Bucharest is Romania's largest city (with over 2 million inhabitants), the
national capital, and one of the great metropoles of southeastern Europe
(GROSEE Espon Project, 2014). Its urban evolution has been very rapid,
largely occurring from the second half of the 19th century. Currently, the
city occupies an area of 228 km2 and possesses a housing stock
predominantly consisting of multifamily apartment buildings, built during the
communist period (Ianos et al., 2016). Located about 135 km from the
epicentre of the Vrancea seismic area (Lungu et al., 2000), in close
proximity to the Southern Carpathian Mountains and at the junction of the
Eastern European, Intra-Alpine, and Moesia plates (Mărmureanu et al.,
2011), the city is extremely vulnerable to earthquakes. Indeed, in a
classification of European metropolitan areas with respect to potential loss
of life and damage to property, Bucharest is ranked second after Istanbul
(Bala, 2014).

The historical record of Bucharest is replete with accounts of damaging
earthquakes ever since the city's founding (Tatevossian and Albini,
2010). The Vrancea seismic area is responsible for the highest seismic risk
in Romania (Pavel et al., 2014; Ardeleanu et al., 2005). Over the past 76 years,
Bucharest has been affected by four earthquakes with a magnitude of
between 6.9 and 7.7 on the Richter scale (November 1940, March 1977, August
1986, and May 1990).

The study area for this paper is confined to central Bucharest, an area of
approximately 8.33 km2 (Fig. 1). The oldest part of the city
is situated in the south of this area, which comprises the historic centre
(from the 16th and 17th centuries) and the central and northern parts
dating from the 18th and 19th centuries. All four earthquakes mentioned above
have impacted this case study area, with the most powerful being the
earthquakes of 1940 and 1977. This sequence of earthquakes has had a
cumulative effect, which explains the relative lack of buildings dating back
more than 200 years.

The most serious problem is presented by the large number of buildings from
the late 19th century within the historic centre, which has structurally
degenerated over time and no longer meets the current building standards
with regard to assessment of the ground motion levels for the Vrancea
(Romania). Not only does Bucharest have a high level of exposure to
earthquake hazards; it also suffers from poorly organized civil protection
services and a low level of public awareness and education concerning these
seismic risks (Armaş, 2006). Nevertheless, anticipation and anxiety are
building, given the length of time that has passed since the 1977 major
earthquake. In essence, there is a fear that the city will be no better
prepared than it was in 1940 (Fig. 2a) or in 1977 (Fig. 2b). These figures
show only a slight improvement in the standard of the disaster measures
between the two dates, and there is a growing recognition that greater levels
of preparedness are needed.

Immediately after the earthquake of 4 March 1977, with about 1700 victims
(Török, 2017), the former regime announced the start of a
rehabilitation project for the highly degraded buildings within the central
area, a project which was abandoned in less than a year. Many buildings,
after being braced in position for 6–7 months with wooden or metal poles
(which were later withdrawn), were then only “cosmeticized” and reoccupied.
These decisions set a precedent for irresponsible policy that, unless it is
addressed and altered, could have disastrous long-term consequences.
Additionally, the growth of complacency over time has been a great enemy, and
a permanent state of vigilance is needed. Finally, there is a need for
considerable public investment in mitigation in the areas most vulnerable to
earthquakes. The lack of wider public awareness of the high seismic risk of
these buildings (identified as a result of surveys conducted in and since
the mid-1990s) is evident in that the apartments in these cosmeticized
blocks are still among the most expensive in the city due to their
central location and spaciousness.

Accordingly, the Romanian government has established the National Committee
for Emergency Situations and the Department for Emergency Situations. The
department coordinates the General Inspectorate of Emergency Situations.
Forty-one local inspectorates cover the city of Bucharest and the department of Ilfov.
The city of Bucharest has three existing meeting points (two in Bucharest and other
in the village of Ciolpani to the north), and there is a special strategy to bring
in instantaneous support from 24 counties surrounding the city.

This assessment of seismic hazard and vulnerability includes quantitative
and qualitative data analysis that incorporates physical, environmental,
social, and economic factors; potential impacts from existing risk maps; and
estimates of the population that would potentially be affected
(Mândrescu, 1990; Armaş, 2012; Rufat, 2013; Pollino et al., 2012). The
accessibility analysis takes into consideration the specificities of each
urban district, especially the urban context (Noto, 2017).

3.1 Data

The authors have used several data sets (buildings classified by seismic
risk and emergency categories, i.e. the presence of hospitals and fire
stations) in order to provide a realistic depiction of the impact that a
potential earthquake could have in the historical centre of Bucharest. Only
those fire stations and hospitals within the municipal limits of Bucharest
are included. The main data sources were provided by public institutions.
Every year the municipality of Bucharest publishes a technical report
classifying buildings with relation to four seismic risk criteria and three
emergency criteria to assess their level of public safety. Table 1 shows the
distribution of Bucharest's buildings by risk and emergency categories.
Special attention is paid to the historic centre of Bucharest, which contains
the largest concentration of buildings which represent a public safety risk.

To represent the accessibility patterns prior and subsequent to an
earthquake, it was necessary to digitize all elements of the transport
infrastructure, construction, green spaces, alleys, sidewalks, and property
limits.

Several different map sources were used to identify building locations,
including cadastral maps at scales of 1 : 500 and 1 : 2000 (IGFCOT,
1974–1975). Other map types and sources include old maps of Bucharest
produced by the Topographic Military Directorate and orthophotomaps (2014)
taken from the National Agency for Cadastre and Real Estate Advertising. The
authors have overlaid accessibility patterns on a numerical model of the
land, given the absence of natural barriers, since the municipality of
Bucharest is located on a plain.

Table 1Building condition data for the historic centre of Bucharest
(number of restored buildings is at the historical centre level; number of fire
stations and hospitals is at the municipality level). RI–RIV: seismic risk
categories; U1–U3: emergency categories.

3.2 Methods

An important methodological contribution on the capacity of a city to resume
urban functions after a seismic event is the study by Goretti et al. (2014)
on how the Crotone urban system could better respond to such disasters. This
study shows the importance of rapid accessibility to collapsed buildings and
to injured people. Our study therefore emphasizes the importance of
immediate accessibility for emergency intervention mechanisms and the need
to provide information to facilitate the proactive actions of
decision makers, who need clear and straightforward directions.

The main methodological steps in mapping accessibility in the central area
of Bucharest were (a) setting up a reference database of all the buildings
with seismic risk; (b) transferring this information to a detailed map of the
identified buildings; (c) identifying indicators of building density and age,
and traffic (including pedestrian) intensity; (d) showing the locations of
all hospitals and fire stations; (e) calculating present-day (before a
possible earthquake) accessibility levels; (f) identifying specific locations
of potential congestion resulting from the collapse of buildings included in
the highest risk class; and (g) determining, by simulation, the immediately
inaccessible or poorly accessible areas for the intervention crews in the case
of an earthquake, taking into account those buildings that might
collapse if an earthquake occurs.

In the scientific literature, “access” is mainly measured as a physical
distance or travelling time (Sotoudehnia and Comber, 2011). In this study,
mapping the accessibility of the central area of Bucharest was completed
using GIS techniques incorporating spatial analysis. The calculation of
accessibility was initially based on the geometric structure of the public
transport network (busses, trams, and underground services), but not on the
walking and cycling networks, which, although they have been included in
other studies, are less amenable to emergency service access in this context
(Graeme and Aylward, 1999; Parker and Campbell, 1998; Naphtali, 2006;
Svensson, 2010; Weiping and Chi, 2011; Sotoudehnia and Comber, 2011; ESPON
TRACC Interim Report, 2011; ESPON GROSEE Final Report – Scientific Report,
2014; Blandford et al., 2012; Coffee et al., 2012; Yiannakoulias et al.,
2013; Vojnovic et al., 2014).

The Kernel Density tool was used to calculate the density of point and line
features in a neighbourhood around those networks. After modelling the road
network using the ArcGIS Network Analyst extension, the authors used an
assortment of analytical tools. These included the New Route tool to check
the road network, the New Closest option to determine the closest emergency
facility (hospital, fire station) to each point, and the New OD matrix
function to determine optimal routes (depending on road distance and travel
time) following the principle of the shortest possible route to establish
links between each pair of points.

To highlight accessibility in the most comprehensive way, the street
structure (which is very dense in the historic centre where the streets are
narrow) and road traffic density had to be taken into account. Accessibility
was calculated as a function of the distances between different buildings
areas and hospitals and of the time necessary for these movements (using
isochrones). Isochrones maps, showing travel times by public transport from
the city centre, had been used to assist in urban transport planning in the
1950s (Kok, 1951, Rowe, 1953 quoted by O'Sullivan, et al., 2000). These
isochrones were generated using GIS.

In addition, the Kriging kernel interpolation calculation and local
polynomial interpolation were used. For exact interpolation, the inverse
distance weighted (IDW) method was used. These methods identified support
elements for more proactive management that have the potential to bring
about a decrease in both the material damage and the human casualties
resulting from a strong earthquake. Using a database in a GIS environment
enabled an assessment and estimation of the potential damage that could be
caused by such an event. At the same time, GIS is a valuable method of
analysis for this purpose because the databases can be regularly updated,
allowing for ongoing mapping of the changing risk scenarios and the updating
or reassessment of potential damage. The risk scenarios also provide useful
identification of the vulnerable areas and population groups (Sinha et al.,
2008).

The penultimate methodological step was to identify likely congestion
locations. The initial simulation assumed that all the buildings categorized
as possessing the highest degree of risk would collapse. For the core of the
historical centre, this permitted the identification of some important sites
and street segments which would be blocked in the case of a strong
earthquake using the location of each highest-risk building, their age and
number of floors, and the local configuration of the street network.

Our intention is not to propose a precise correlation between the
vulnerability of buildings (based on all their characteristics) and the
intensity of the next earthquake. Rather, especially by taking into account
that some of buildings in this area have partially collapsed in the absence
of a direct seismic cause, we contend that an earthquake of similar
magnitude to the 1977 event would produce outcomes comparable to our
simulation.

From this information several maps were developed taking into account the
region's particular seismogenic characteristics (Mäntyniemi et al.,
2003). Two offer general images of accessibility at the city level closely
correlated with the territorial distribution of fire stations and hospitals.
Another identifies areas or street segments potentially isolated by building
collapses.

In recent years, scientific approaches to risk reduction of natural events,
such as earthquakes, have used resilience as an important concept, which
could offer new theoretical and practical tools for better civil protection
(Fekete and Fiedrich, 2018). Using this concept, scientists are paving the
way for reinvigoration of the expectations, by joint actions with decision
makers and civilians (Anhorn, 2018). These ideas ask whether
other complementary issues are connected with a higher accessibility to the
affected areas.

Our approach, focusing on the single issue of accessibility in a situation
of crisis management, shows empirically how GIS technologies can be used to
make recommendations to authorities to improve their preparedness levels and
response speeds in post-earthquake interventions. Within this study, GIS is
used solely as a tool to identify accessibility as a starting point for
disaster management (Nushi and van Loenen, 2013). These GIS solutions are
demonstrably important applications in relation to the first two phases
(risk mitigation and disaster preparedness) of Alexander's (2002) four-phase
sequence of emergency management activities.

It is necessary to simulate emergency interventions prior to the occurrence
of catastrophic events because, in the local situation, the inherited
intra-urban structure, with a narrow winding street pattern dating back to
medieval times; the poor structural condition of many of the buildings; and
limited access to important points from the emergency response activity
locations are all of critical importance.

In such a context, accessibility to specific disaster sites is critical, and
this requires that urban areas of this nature be treated with special
attention. The biggest challenge may be caused by traffic congestion
compounded by debris, which can isolate critical areas, making rapid
intervention to put down fires and save human lives impossible.

The official identification of buildings with a high seismic risk combined
with precise mapping of their location can be related to the density of road
traffic in the historic areas (Fig. 3). If traffic is very high on the main
access streets, this could inhibit rapid intervention, especially in a
situation of general panic such as that generated by a potential earthquake. It
would also be difficult to use narrow streets, where the pedestrian traffic
and partially collapsed buildings could block the access of emergency
service vehicles. In this context, there is a need for proactive measures,
to mitigate the risk of late arrival of assistance at the affected
buildings.

The most important area of the historical centre is the one delimited by
Armenească, Moşilor, and Călăraşi streets; Splaiul
Independenţei; Calea Victoriei; and Carol and Regina Maria boulevards.
Within this area, the building density exceeds 2.5 units ha−1; in
some places, it even exceeds 10 units ha−1. In the areas of the highest density,
most of the buildings have two or three floors, and, because of their
uncertain legal status after 1990, many exhibit an advanced and increasing
degree of dilapidation. Restoration and reinforcement of these buildings by
both public authorities and private entrepreneurs are only proceeding at a
maximum rate of two buildings per year.

The number of buildings with the highest seismic risk (computed with the Kernel
Density tool) shows a very high concentration in the historical centre of
Bucharest (Fig. 4). When looking at a map of seismicity at the level of
Bucharest, it becomes obvious that the inherent risks from earthquake damage
are greatest in central Bucharest, including the historical centre (Rufat,
2011). Even though most of the buildings located in the historical centre
date from the early 20th century, they were built on the foundations of 19th-century structures (Armaş, 2008).

Figure 4Density of buildings with a major seismic risk. (1) Building;
(2) Dâmboviţa River; (3) core of the historic centre.

To highlight the anticipated degree of access for fire protection and
ambulance services in the central area, accessibility levels prior to an
earthquake were calculated and later compared to a post-earthquake scenario.
Taking into account the location of the fire stations and hospitals, and the
street tram network, the access routes into and within the study area were
evaluated using the Network Analysis tool. Thus we identified the shortest
routes from the closest emergency facilities (fire stations and hospitals) to
all locations in the study area, using the Bellman–Kalaba algorithm. These
minimal road applications were applied for various types of emergency
service: transport, ambulance, fire, police, etc.

It was noted that both firefighting and ambulance service accessibility
were high or very high for most parts of the capital city, including the
downtown area, which is especially well served by firefighter and ambulance
services. There are 13 large fire stations in Bucharest. However, the lowest
levels of potential accessibility by fire services to individual houses in
the city of Bucharest occurred in the historic centre area, mainly due to the
configuration of the street pattern (Fig. 5). The lowest values were
registered in an area between Calea Victoriei, Doamnei Street, Brătianu
Boulevard, and Splaiul Independenţei, in the core of the historic centre. Low values
occur to the east of Brătianu Boulevard, even though some important access
axes (Armenească, Calea Moşilor, Hristo Botev, Negustori) are located
nearby. Overall, if fires broke out at several different points in the
historic centre core during a seismic event, this would present huge
problems.

The map of ambulance accessibility (Fig. 6) presents a very similar picture.
However, access is better in the northern part of the historic centre due to
the location of Colţea Hospital. Figure 7 shows two areas where it would
be difficult for ambulances to arrive in a timely manner, one in the core of
the historical centre and the other in the surrounds of Mihai Vodă
Street, which would be accessed by ambulances from University
Emergency Hospital.

Should an earthquake occur, an important consideration is the challenge
presented by building collapses which obstruct road access. Identifying
individual buildings with the highest levels of seismic risk highlighted the
possibility of concentrated building collapses in certain locations within
the historic centre. In these the locations, some buildings would become
isolated, and rapid intervention by fire or ambulance services would be
impossible.

This general analysis indicates that the central area seems to be favoured
due to the possibility of intervention from several emergency service points
into this part of the city. However, and in spite of this, pedestrian and
vehicular congestion is highly likely to inhibit rapid access by
firefighters and ambulances in several areas within the central district.
Also, several locations in the downtown area, which previously appeared to
have high emergency accessibility levels, were shown to possess high
probabilities of multiple building collapses. These events could well
obstruct access by emergency vehicles, despite the high levels of
accessibility that were identified initially.

Should an earthquake with a magnitude of over 7 on the Richter scale occur,
fires would present a major associated risk. The majority of the city centre
buildings are of timber construction or possess many timber components (some
buildings from Şelari Street, e.g. “Crama Domnească”; Covaci
Street; and Smârdan Streets, for example). These buildings
characteristically house restaurants, cafes, or pubs, which contain huge
quantities of furniture, a further important source of fire. If emergency
action does not occur promptly, in such locations, the probability of
numerous fatalities is high. In addition, water supply and sewerage systems
may be damaged, resulting in basement and ground floor flooding. It would
therefore be advisable to provide supplementary emergency response materials
at a large number of locations within this district. This would allow access
to such equipment at the local scale as an alternative to the provision of
emergency materials and services from elsewhere which may be unobtainable in
the event of an emergency.

Assuming that, in the event of a large-scale disaster, certain clusters of
buildings may become isolated and inaccessible to emergency services, it is
therefore recommended that smaller-scale aid stations be established within
these districts. These smaller-scale aid stations could then provide
critical assistance in areas isolated by building collapses.

A detailed analysis highlights the fact that in the southwestern part of the
historical center of Bucharest there is an area that includes several buildings
of national importance (the parliament building, the headquarters of several
ministries and other public institutions). In the proximity of this area are
located several emergency services that may be oriented to ensure the protection
of these public institutions, rather than the provision of services to areas
with high densities of buildings with high seismic risk.

The map which shows both the distribution of the highest seismic risk
buildings and the location of the nearest fire stations (Fig. 7)
illustrates the need for greater proximity (and hence access) of fire
stations to the two areas of maximum density of highest-risk buildings: one
in the Lipscani area and the other in the Bărăţiei area. The
western area (Griviţa–Gara de Nord) could be placed under the
authority of the two existing fire stations. These areas of high
vulnerability should be connected to a permanent emergency water supply
(since the normal water sources would be disrupted by an earthquake). They
should also possess a minimum, yet sufficient, level of equipment for a
local first response.

The location of hospitals again appears to be favourable at first glance
(Fig. 8), but their capacity should be assessed against the probable number
of casualties, which could reach as high as 11 000. The earthquake of 1940
registered 1271 and the 1977 earthquake 11 321 injured persons (Pavel and
Văcăreanu, 2015). The location of Colţea Hospital suggests that
the majority of injured persons would go there for immediate treatment.
However, this hospital only possesses a small surgical unit (with three
operating theatres), and it would be unable to offer emergency medical
assistance to a large number of persons over a short period.

Figure 8The territorial distribution of hospitals in the central area and
their relationship to buildings with a high seismic risk. (1) Building;
(2) hospital; (3) core of the historic centre.

To increase the efficiency of emergency response, the location and number of
potential casualties must be more precisely determined. Consideration needs to be
given to the availability of specific medical services at individual
hospitals and other medical facilities. The provision of surgical wards,
imaging laboratories, and orthopaedic facilities is more uneven than the
provision of hospitals more generally across the city. Depending on the
territorial distribution of these specific hospital services, the buildings
with highest seismic risk should be assigned to specific emergency hospital
services so that accessibility levels can be maximized. Obviously, this
implies the designation of dynamic territorial structures, which, depending
on the gravity of the reported seismic events and their human consequences,
would include access to other hospitals at greater distances from the
central area (Toma-Dănilă, 2013).

Figure 9The anticipated spatial effects of building collapse in a similar
earthquake to that of March, 1977. (1) Building in the first category of risk
(R1); (2) Isolated areas resulting from the hypothesis that all buildings
belonging to the R1 class would collapse; (3) Blocked street segments.

There are some studies on firefighting simulation outside of the historical
centre of Bucharest, for example on Magheru Boulevard, which reveal the
importance given to this related phenomenon with an earthquake event
(Fiedrich, 2007). In the event of a powerful earthquake, a partial or even
total breakdown of communication systems is likely. This eventuality would
cause many people to make direct contact with friends and relatives by
moving around the city by car. Rapid intervention by the traffic police would
be vital to minimize congestion in those areas of the city where the need
for emergency intervention is greatest.

The unpredictable nature of this phenomenon may well lead to traffic
bottlenecks at unanticipated locations along the transportation network,
which in turn would further complicate rescue, relief, and evacuation
efforts. In these circumstances, communication systems between those who
would be mapping the collapsed or damaged buildings and those who would be
ensuring the traffic flow need to function as smoothly as possible in order
to allow the wounded to be transported to hospitals and the fire engines to
move towards critical spots in the city. Where the simultaneous collapse of
buildings, especially in the medieval area of the city, made rapid
intervention impossible, lifesaving equipment, individually transported by
specially trained persons, would be needed to provide immediate assistance.

Our study has sought to demonstrate what could happen in the core of the
historic centre (Fig. 9), taking into consideration the likely collapse of
buildings classified as risk 1 (R1). Any future earthquake of more than 7.2
on the Richter scale (the level of the strongest recent earthquake on 4 March 1977)
would pose an amplified danger of the collapse of buildings
at critical locations. We define critical locations as those where building
collapse could block access to specific areas or street segments.

These potential blockages are most likely to occur in five areas, identified
in Fig. 9 as A, B, C, D, and E. Area A (Blănari area) is small and
delimited by building no. 2 (built in 1865, three floors) and the buildings
from no. 9 (1880, five floors) to no. 14 (1935, six floors). Area B
(Lipscani–Gabroveni area) is the largest site and contains a group of 15
vulnerable buildings. Possible street blockages could be produced by the
collapse of buildings on Lipscani Street, such as no. 26 (1864, five floors)
or no. 29 (1934, nine floors) along with no. 76 (1906, four floors), and on Gabroveni Street, such as
buildings no. 2 (1940, nine floors) and no. 12 (1924, six floors). Two other
areas, C and D, are respectively located on
Franceză Street between buildings no. 6 (1869, five floors) and no. 22
(1900, six floors), and between buildings no. 30 (1870, five floors) and
no. 42 (1870, five floors). On the west side of the main boulevard,
Bulevardul Ion C. Brătianu, area E (Bărăţiei) contains
building no. 8 on Baia de Fier Street (1930, five floors) and buildings
no. 37 (1870, three floors) and no. 50 (1824, four floors) on
Bărăţiei Street.

A final consideration is that, for much of the day, the core of the historic
centre normally contains between 1000 and 5000 visitors in addition to the
area's residents and workers. This only adds to the need to devise proactive
earthquake intervention and mitigation strategies.

We therefore suggest the following proactive measures to mitigate the risks
associated with a seismic disaster in the city of Bucharest, especially within
the core of the city's historic centre:

the constitution of a technical team of decision makers to identify
optimal response strategies for a future earthquake, whose main task
would be to identify the critical points and areas for emergency
intervention in the most congested areas (Tuns et al., 2013);

the prioritization of building consolidation, correlated with the
buildings' locations and their potential to block street segments and
critical access routes in the event of their collapse;

the re-evaluation of the number and locations of fire stations;

the development of a system of emergency medical aid posts within the
historic centre, taking into account both the area's access problems and the
fluctuating population of the area resulting from its entertainment role;

reorganization of Colţea Hospital, including the expansion of its
infrastructure (especially the surgical section, and the number of operating
theatres). This hospital should become the most important point of emergency
intervention in the historic centre of Bucharest in the event of a strong
earthquake.

This study demonstrates that GIS can be used effectively as an analytical
and decision-making tool in planning for hazard mitigation. GIS, when properly
employed, can provide information concerning emergency response
accessibility in areas where physical structures are degraded and pose a
higher risk of collapse. Such knowledge is critical in anticipating the
impact of a disaster. Injury, loss of life, and damage to property can be
minimized through more effective and rapid emergency response.

In Europe, Bucharest ranks second, after Istanbul, in its exposure and risk
related to earthquakes. It is not enough to be familiar with the
distribution of the high-seismic-risk buildings. Emergency intervention is
also vital to minimize the consequences of such an event. In order to save
lives, knowledge of accessibility levels and related rapid intervention
potential is essential in the event of an earthquake. However, the current
status and priorities of natural hazard and emergency response planning in
the city of Bucharest (and at the national scale) are such that they are
unlikely to mitigate the effects of a potential disaster to a sufficient
extent. Across several measures – the training of specialists, public
awareness and education, infrastructural improvements, and building
improvements – current efforts are inadequate.

The passivity of urban decision makers in relation to the very large number
of buildings in the highest risk class is perhaps the most surprising element
here. These buildings are concentrated in the most populated and attractive
areas of the city in terms of leisure and entertainment. Even if Bucharest's
inhabitants are partially aware of this risk, the vast majority of tourists
are unlikely to realize what could happen should an earthquake occur.

The most recent major disaster event that took place in Bucharest – the fire
in Club Colectiv on the night of 30 October 2015, which
led to the deaths of 63 people and serious injury to around 150 – brought
the major risk that an earthquake can pose to the attention of the local and
national authorities. In response, a ban was imposed on all shops,
restaurants, and clubs operating in buildings with high seismic risk, but
there are not enough resources to refit the high-risk buildings that continue
to be inhabited. This event reminded the population and the authorities that
an earthquake event or disaster of similar scale will occur again at some
point and that it is necessary to have a clearly defined policy that relies
upon concrete measures to reduce the human and material losses.

Our study reveals both the importance of accessibility to buildings for
emergency intervention and the shortcomings in the current provision of
major emergency response services. Our methodology, using simple tools,
offers analysts and decision makers a credible means of developing a
proactive vision of and a management strategy for emergency response in
congested historic areas. GIS is a commonly used tool for analyses of this
type, and its results, since they can be expressed cartographically, can be
more widely understood than is often the case when other statistical and
computational techniques are employed.

CM and II designed the study. GM, CM, and II established and set up the maps.
II, CM, RJ, GM, and GP analysed and interpreted the results. II and CM wrote
the paper with substantial input from all co-authors. RJ revised the
English.

A simulation of the building collapses and street blockages that are most likely to occur in the event of the next major earthquake in the historic centre of Bucharest was conducted in order to evaluate their impact on the provision of disaster response and emergency services. It identified those areas where the accessibility impacts would be most severe. These results are of value to local policy makers and planners seeking to devise targeted and effective disaster response strategies.

A simulation of the building collapses and street blockages that are most likely to occur in the...